Conventionally, an image processing apparatus for printing by adding transparent ink (hereinafter referred to as clear ink) to colored inks is known. As clear ink, for example, a one for making colored inks unnecessary (for example, Japanese Patent Application Publication No. Hei 8-072230), a one for improving the glossy feeling (for example, Japanese Patent Application Publication No. 2004-001410), and a one for preventing ozone color fading (for example, Japanese Patent Application Publication No. 2005-014223) are known.
And, as a method for deciding the dot arrangement position and amount of the aforementioned clear ink, a method for generating quantized data for clear ink on the basis of the quantized data of colored ink obtained by performing the multilevel halftone process at a rough resolution and arranging dots of clear ink on the basis of the concerned quantized data for clear ink is known (for example, Japanese Patent Application Publication No. Hei 11-334114).
Further, a method for retaining beforehand the dot arrangement pattern of clear ink and on the basis of the dot arrangement pattern of the concerned clear ink, arranging dots of the clear ink is also known (for example, Japanese Patent Application Publication No. Hei 9-272203).
Further, a method for calculating the ink adhesion amount of colored ink in a predetermined print area and on the basis of the ink adhesion amount of the concerned colored ink, deciding the clear ink adhesion amount and arrangement position is also known (for example, WO 2004-069543). The method described in the Patent Document No. Hei 11-334114 has advantages that the burden imposed on the operation is little because the clear ink feed step is simple and the processing speed is fast.
However, the method described in the Patent Document No. Hei 11-334114 performs the half-tone process at a rough resolution, so that a problem arises that the image quality is deteriorated. Further, in the method described in the Patent Document No. Hei 9-272203, in the dot arrangement pattern in a small area, periodicity appears in the clear ink dot arrangement, thus irregularities may be caused, so that it is necessary to retain the dot arrangement pattern in a large area and a problem arises that a large capacity memory is necessary. Further, in the method described in the Patent Document WO 2004-069543, for example, in a solid image in which colored ink is arranged in the same pattern, the clear ink arrangement becomes a fixed pattern, so that irregularities of clear ink may be caused.
An object of the present invention is to provide an image recording apparatus, an image recording method, and an image recording program for preventing an occurrence of irregularities of clear ink, requiring no large capacity memory, and impairing no processing speed.